linux-ext4 - [PATCH 04/10] fuse_trace: use the iomap cache for iomap

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Message-ID: <176169812163.1426649.18234833679814805780.stgit@frogsfrogsfrogs>
Date: Tue, 28 Oct 2025 17:57:13 -0700
From: "Darrick J. Wong" <djwong@...nel.org>
To: djwong@...nel.org, miklos@...redi.hu
Cc: joannelkoong@...il.com, bernd@...ernd.com, neal@...pa.dev,
 linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH 04/10] fuse_trace: use the iomap cache for iomap_begin

From: Darrick J. Wong <djwong@...nel.org>

Add tracepoints for the previous patch.

Signed-off-by: "Darrick J. Wong" <djwong@...nel.org>
---
 fs/fuse/fuse_trace.h |   34 ++++++++++++++++++++++++++++++++++
 fs/fuse/file_iomap.c |    7 ++++++-
 2 files changed, 40 insertions(+), 1 deletion(-)


diff --git a/fs/fuse/fuse_trace.h b/fs/fuse/fuse_trace.h
index f6c0ff37e7d570..8f06a43fd2d69a 100644
--- a/fs/fuse/fuse_trace.h
+++ b/fs/fuse/fuse_trace.h
@@ -401,6 +401,7 @@ struct fuse_iomap_lookup;
 
 #define FUSE_IOMAP_TYPE_STRINGS \
 	{ FUSE_IOMAP_TYPE_PURE_OVERWRITE,	"overwrite" }, \
+	{ FUSE_IOMAP_TYPE_RETRY_CACHE,		"retry" }, \
 	{ FUSE_IOMAP_TYPE_HOLE,			"hole" }, \
 	{ FUSE_IOMAP_TYPE_DELALLOC,		"delalloc" }, \
 	{ FUSE_IOMAP_TYPE_MAPPED,		"mapped" }, \
@@ -1474,6 +1475,39 @@ TRACE_EVENT(fuse_iomap_cache_lookup_result,
 		  FUSE_IOMAP_MAP_PRINTK_ARGS(got),
 		  __entry->validity_cookie)
 );
+
+TRACE_EVENT(fuse_iomap_invalid,
+	TP_PROTO(const struct inode *inode, const struct iomap *map,
+		 uint64_t validity_cookie),
+	TP_ARGS(inode, map, validity_cookie),
+
+	TP_STRUCT__entry(
+		FUSE_INODE_FIELDS
+		FUSE_IOMAP_MAP_FIELDS(map)
+		__field(uint64_t,		old_validity_cookie)
+		__field(uint64_t,		validity_cookie)
+	),
+
+	TP_fast_assign(
+		FUSE_INODE_ASSIGN(inode, fi, fm);
+
+		__entry->mapoffset	=	map->offset;
+		__entry->maplength	=	map->length;
+		__entry->maptype	=	map->type;
+		__entry->mapflags	=	map->flags;
+		__entry->mapaddr	=	map->addr;
+		__entry->mapdev		=	FUSE_IOMAP_DEV_NULL;
+
+		__entry->old_validity_cookie=	map->validity_cookie;
+		__entry->validity_cookie=	validity_cookie;
+	),
+
+	TP_printk(FUSE_INODE_FMT FUSE_IOMAP_MAP_FMT() " old_cookie 0x%llx new_cookie 0x%llx",
+		  FUSE_INODE_PRINTK_ARGS,
+		  FUSE_IOMAP_MAP_PRINTK_ARGS(map),
+		  __entry->old_validity_cookie,
+		  __entry->validity_cookie)
+);
 #endif /* CONFIG_FUSE_IOMAP */
 
 #endif /* _TRACE_FUSE_H */
diff --git a/fs/fuse/file_iomap.c b/fs/fuse/file_iomap.c
index 42cb131e1ee36a..ed7e07795679a6 100644
--- a/fs/fuse/file_iomap.c
+++ b/fs/fuse/file_iomap.c
@@ -1575,7 +1575,12 @@ static bool fuse_iomap_revalidate(struct inode *inode,
 		return true;
 
 	validity_cookie = fuse_iext_read_seq(&fi->cache);
-	return iomap->validity_cookie == validity_cookie;
+	if (unlikely(iomap->validity_cookie != validity_cookie)) {
+		trace_fuse_iomap_invalid(inode, iomap, validity_cookie);
+		return false;
+	}
+
+	return true;
 }
 
 static const struct iomap_write_ops fuse_iomap_write_ops = {